Sedimentary rocks (outcropped)

Hydrogeological Context

Version	Metadata
	0ea68738-1bd5-4755-9ed6-ce341fd5f47c

Project
Portneuf

Update:2014-01-29

Physiography
The sedimentary rocks include limestones of Trenton Group and shales of Utica Group. These are highly fractured rocks, very friable in the case of shales, and affected by the dissolution process that led to an early karstification in limestone of St. Casimir and Pont-Rouge. The sedimentary rocks outcrop on some sections along the St. Lawrence River, creating unconfined conditions. The aquifer is vulnerable to contamination from the surface. Surface water infiltrates and flows through fractures and voids in the rock. The aquifer potential is good and water calcium bicarbonate-type show low mineralization.
Hydrogeological region	St. Lawrence Platform
Hydrogeological context
Relief	The outcropping sedimentary rocks have a flat terrain. They are located along the St. Lawrence River. The sedimentary rocks altitudes are among the lowest observed in the region.
Area	149.00 km2
Lithology
Description	The Paleozoic rocks of the sedimentary platform are mainly composed of limestones of Trenton Group and shales of Utica Group. The regional dip of these rocks is 1 ° to 2 ° to the south. These are highly fractured rocks, very friable in the case of shales, and affected by the dissolution process that led to an early karstification in limestone of St. Casimir and Pont-Rouge.
Source
Aquifer
Aquifers	List of aquifers sedimentary rock aquifer

Bedrock aquifer media


Typical value:	karst - fractured
Description	The Paleozoic rocks of the sedimentary platform are mainly composed of limestones of the Trenton Group and shales of Utica Group. The limestones of St-Casimir and Pont-Rouge sectors show a beginning of karstification.

Confinement

Typical value:	unconfined

Well depth
36.45 m Range: [0.3 to 121.9] m

Groundwater depth
0.21 m Range: [0 to 4.82] m

Regional precipitation
1121.5 mm/y Range: [1063.1 to 1168.2] mm/y
Methode	Precipitation data are from Environment Canada. The value represents the average of the climate normals (1981-2010) measured on the stations distributed in or near the hydrogeological unit. The stations were selected so the average precipitation is as representative as possible of the whole hydrogeological unit.

Hydrogeological unit potential

Description	The outcropping sedimentary rocks show a good aquifer potential.

Aquifer vulnerability
3 Range: [0 to 5]

Groundwater Quality

Description	Water is low mineralized and is the type calcic bicarbonate.